Tenneco Packaging Inc.

Mobil Oil Corporation

Donald E Rowe

Glenn C Castner

Keith A Messinger

Kenneth James Simmons

Phillip S Baker

Richard A Cummings

A disposable food container comprises a lid and a base optionally connected to each other along a resilient hinge. The lid includes a top wall, a continuous lid side wall, and a plurality of lid corners. The lid side wall encompasses the top wall and extends downwardly and outwardly from the top wall. The plurality of lid corners are at least partially formed by the lid side wall and include a pair of front lid corners. The base includes a bottom wall, a continuous base side wall, and a plurality of base corners. The base side wall encompasses the bottom wall and extends upwardly and outwardly from the bottom wall. The plurality of base corners are at least partially formed by the base side wall and include a pair of front base corners. If the container is provided with a resilient hinge, the pair of front lid corners and the pair of front base corners are spaced away from the hinge. The container includes a corner latch closure for releasably engaging the lid and the base in a closed position. The corner latch closure includes at least a pair of slots and at least a pair of slot engaging structures that can be interlocked with each other. The pair of slots are formed by the respective front base corners, while the pair of slot engaging structures are formed by the respective front lid corners.

Container with a corner latch closure

The invention relates to a mold apparatus and a process for forming a lid latching mechanism in a thermoplastic container. The lid latching mechanism features a large, trapezoidally-shaped opening hole. The trapezoidal shape has been found to reduce the amount of tearing that can occur along the edges of an opening formed during the thermoforming process. The opening is created by the engagement between a fixed shear key mounted in a first mold member and a movable shear key which has a trapezoidally-shaped cutting surface and is mounted in a second mold member. The movable key travels along an inclined path as the mold members close on a preheated thermoplastic sheet to form a container.

Hinged lid latching mechanism

Process for making a trapezoidally-shaped opening in a thermoformed

Hinged lid container with releasable locking means

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Newark, NY, United States of America

Donald E Rowe